This invention relates to a golf club of the xe2x80x9cputterxe2x80x9d type, with a club head which has a level, or largely level, strike area. When using a putter to put a golf ball on a putting green, the golfer usually strikes the ball applying a non-spinning stroke to move the golf ball along a desired path which gives it a rolling movement along the grass on a plane parallel with the plane of the roll. When a golf ball is to be putted into the intended hole it is important that the ball is given a controlled path of movement, preferably with a controlled roll in the direction of movement. In this connection, the aim is normally to give the ball an even rolling movement over the surface, i.e. with rolling contact with the grass on the green, and preferably without causing the ball to jump unintentionally on the grass. Using this invention, the aim is to give the golf ball an intentional spin as soon as the stroke is played. In other words, it is desirablexe2x80x94at least with certain putting strokesxe2x80x94to transfer a large part of the kinetic energy from the golf club to the golf ball thereby causing the ball to take on a spinning movement, i.e. instead of applying a non-spinning stroke to the ball, a stroke is played which gives the ball a combined thrust and spinning movement. Until now, the golf ball has been given an intentional spin of this kind by, for example, holding the strike area of the putter at an appropriately oblique angle. Alternatively, the putter can xe2x80x9ctopxe2x80x9d the golf ball by striking it at a level above its the horizontal mid-plane. The strike area of the putter normally has a vertical position when the putter is in a normal vertical position in connection with a putting stroke. But by having the strike area at an oblique angle in relation to the vertical plane one may deliberately seek to create great friction between the golf ball and the grass of the green already in the very first phase of the ball""s rolling movement as a result of the obliquely angled stroke played against the golf ball. Consequently, the aim is to apply as controlled a spin as possible to the golf ball at an early stage in the movement of the golf ball. In practice, however, in many cases the point at which the spin starts after the stroke has been played is a matter of chance, and also the degree of spin, since after being struck by the golf club the golf ball, in certain cases, may be given a rapid upward lifting movement from the underlying surface and may therefore make a subsequent soaring movement in relation to the underlying surface. Thus, the golf ball is given a limited or more or less uncontrollable spin. Until now, the position of the strike area of the putter in relation to the golf ball has been very decisive for the movement of the golf ball in relation to the underlying surface. However, local conditions (humidity/dampness, unevenness etc.) on the green affect, to a varying degree, the friction of the golf ball and thereby its speed of movement and pattern of movement, including the spin movement and the speed of the spin. When the player""s putter stroke meets the golf ball in an area above the horizontal mid-plane of the ball, the golf ball may experience an element of downward force in the direction of the grass on the green, with the result that one achieves intentionally greater friction and an intentional spin on the golf ball at an early stage of the stroke, thereby allowing the ball to roll in an intentional spinning plane and obtaining the gyro effect. Further, when the player places the strike area of the putter at an oblique angle upwards and forward, it is possible, by applying this intentional initial friction against the grass, to ensure that a controlled pattern of movement of the golf ball is achieved in more or less continuous contact with the grass during the rolling movement. On the other hand, if, for example, the player places the strike area of the putter at an oblique angle upwards and backward, it is possible to give the golf ball an intentional soaring or jumping movement, in cases where this is desired.
Using this invention, the aim is to arrive at a solution whereby the putter can give the golf ball a relatively soft and sensitive stroke whereby the gyro effect is obtained at an early stage after the stroke. The level of power transferred is adjustable and where the putter, in this connection, can easily give the golf ball the exactly desired movement by giving it the intended spin and the desired gyro effect. The aim is to ensure that the intended spin movement of the golf ball can be effected directly from the strike area of the putter, i.e. at an early stage in the stroke of the putter against the actual golf ball and with easy and sensitive control of the stroke and to overcome the inertia force of the ball. This can be achieved by arranging the strike area of the putter in such a way that an interchangeable/replaceable longitudinal, lengthwise extended tension bar is attached to two fastening points at each end of the putter head through the two opposite ends of the tension bar, and with the lengthwise tension bar, attached through the two opposite ends, stretching freely over a hollow in the putter head. Using, the lengthwise extended tension bar, which extends freely over a hollow in the putter head, it is possible to achieve some softening of the putter stroke against the golf ball and at the same time have the possibility of giving an initial spin to the golf ball immediately on striking the ball. According to the invention, by ensuring that the said tension bar is locally pliable it is possible to achieve a relatively extensive, i.e. a relatively wide strike area between the putter head and the golf ball. By giving the said tension bar a relatively smooth and low-friction strike surface it is possible to ensure that there is low friction between the putter head and the golf ball in order to deliberately cause the golf ball to have the intended spinning movement. This can also be further controlled, for example by raising or lowering the putter head in relation to the centre of gravity of the ball. A delayed transfer of the force (kinetic energy) from the putter head to the ball will give a smoother and softer stroke. This greatly affects the ball and causes the ball to spin immediately after the stroke. The spin is desirable immediately after the stroke in order to obtain the gyro effect, which in turn gives better stability both in direction and length. Other features of this invention are shown in the following description with reference to the accompanying drawings, as follows: